1. EGGS

2. Everyday Eggs The eggs we most commonly get from the grocery store are produced by hens (chickens) People eat eggs from other birds, including Quail and Duck Can you think of other eggs we eat?

3. About those hens… Hens require a balance diet of grains, proteins, fats, vitamins and minerals. A nutritious diet will affect the quality of the eggs produced. Chickens are fed wheat, corn, barley, rye, oats, soybeans and seeds. Chickens are naturally omnivorous, and in the field will eat worms, insects and small reptiles. In Canada, the feed for laying hens is required to be steroid and hormone-free.

4. Why is that shell a different colour? The colour of the egg shell is determined by the breed of hen, and does not affect the quality, taste, or cooking performance Why is that yolk darker? The colour of the yolk is determined by the feed the chickens were given. A wheat-based diet will produce a paler yolk, while a corn- based diet will produce a darker yolk. This will vary in Canada depending on what is produced locally. Why is that egg bigger? The size of the egg is determined by the age of the hen. As the hen gets older, the eggs get bigger.

5. Grading Eggs Grade A eggs in Canada are categorized by weight. The sizes of eggs are: Eggs are weighed electronically and then stored in a carton with a best before date on it. This is usually 28 – 35 days after packing. Pee WeeSmallMediumLargeExtra LargeJumbo Less than 42g At least 42g At least 49g At least 56g At least 63g 70g or more

6. Storing Eggs Eggs should be stored wide side up because it keeps the yolk properly centered. Eggs should be stored in the back of the refrigerator on the coolest shelf. Eggs have a shelf life of 35 days How can you test if an egg has gone bad? Water test: place the egg in water. If it sinks to the bottom, it is fresh If it stays at the bottom but balances on one end, it is probably expired, but is still usable. If it floats, it has gone bad.

7. Anatomy of an Egg

8. Eggshell – The outer eggshell is made almost entirely of calcium carbonate (CaCO3) and is covered with as many as 17,000 tiny pores. It is a semipermeable membrane, which allows air and moisture to pass through its pores. The shell also has a thin outermost coating called the bloom or cuticle that helps keep out bacteria and dust. Shell membrane – These two membranes – outer and inner – are just inside the shell surrounding the albumen (white). The two membranes provide an efficient defense against bacterial invasion and are made partly of keratin. The outer membrane sticks to the egg shell while the inner membrane sticks to the albumen. When an egg is first laid, it is warm. As it cools, the contents contract and the inner shell membrane separates from the outer shell membrane to form the air

9. Thin albumen (outer thin albumen) — The outer thin albumen is a narrow fluid layer next to the shell membrane. Thick albumen (inner thick albumen) -The inner thick white is a dense, matted, fibrous capsule of albumen around the vitelline membrane of the yolk. The matted fibrous capsule terminates on each end in the chalazae, which are twisted in opposite directions and serve to keep the yolk centered. This part of the egg is a excellent source of riboflavin and protein. In high-quality eggs, the inner thick albumen stands higher and spreads less than thin white. In low- quality eggs, it appears thin white.

10. Vitelline membrane – The clear casing that encloses the egg yolk. When an egg is said to be “mottled”, the yolk surface is covered with many pale spots or blotches. The strength and integrity of the vitelline membrane are very important in preventing egg yolk mottling. Yellow yolk – a major source of vitamins, minerals, almost half of the protein, and all of the fat and cholesterol. The yolk contains less water and more protein than the white, some fat, and most of the vitamins and minerals of the egg. These include iron, vitamin A, vitamin D, phosphorus, calcium, thiamine, and riboflavin. The yolk is also a source of lecithin, an effective emulsifier.

11. Chalaza - which are twisted in opposite directions and serve to keep the yolk centered. The more prominent the chalazae, the fresher the egg. chalazae, which are twisted in opposite directions and serve to keep the yolk centered. Air cell – An air space forms when the contents of the egg cool and contract after the egg is laid. The air cell usually rests between the outer and inner membranes at the eggs larger end. As the egg ages, moisture and carbon dioxide leave through the pores of the shell, air enters to replace them and the air cell becomes larger.

12. Good to know… The chances of being exposed to salmonella from a raw egg are about 1 in 10 000 If you want a perfectly fried egg, cook it as slow as possible over low heat You can freeze raw eggs, but you have to crack them first! Put them in an ice cube tray! Why do some eggs have blood spots? When the yolk is travelling down the reproductive tract of the hen, it can pick up some blood cells before being surrounded by the albumen. It is harmless and does not mean the egg is fertilized.